下丘脑生长抑素神经元——PAP免疫电镜观察

SOMATOSTATIN (SRIF) -IMMUNOREACTIVE NEURONS OF THE RAT HYPOTHALAMUS——AN PAP ELECTROMICROSCOPIC STUDY

本实验以包埋前PAP免疫电镜技术对大鼠下丘脑生长抑素(SRIF)神经元胞体或纤维进行观察,结果表明:下丘脑内SRIF神经元呈三种不同亚微结构特征。其中两种类似一般产生调节激素的小细胞神经元。而另一种细胞器发育类似于神经分泌大细胞。在室周核(Pv)和室旁核(PVN)内的SRIF神经元之间可见多种类型突触。下丘脑腹内侧核(VMN)、弓状核(ARN)、视交叉上核(SCN)内常见许多免疫反应阳性终末轴突与其它阴性树突形成突触联系,正中隆起(ME)处可见SRIF轴突与其它免疫反应阴性轴突形成轴—轴突触,上述结果表明:(1)下丘脑SRIF神经元有三种功能状态的神经元,(2)Pv,PVN内SRIF神经元具有同步活动,超短反馈的形态基础,(3)Fv似外的SRIF神经元参与对局部核团的功能调节。

PAP clectromicroscopic techniquewas used to study the ultrastructure of SRIF-immunoreactive neurons in periventricular nucleus (Pv), paraventricular nuclcus(PVN), superchiasmatic nucleus (SCN), arcuate nucleus(ARN), ventromedial hypothalamic nucleus(VMN) and median cminence(ME). There are three characters of SRIF neurons. The third one was similar to the neurosecretory magnocellular neurons and made more synaptic contacts with other processes than other two kinds of SRIF neurons. In Pv and PVN, the axon-dendritic, dendrodendritic, soma-somatic synapses and the direct somato-somatic oppositions among the SRIF-immunoreactive neruons and processes were usually seen. In other areas, the lebeling axon made synaptic contact with unstaining dendritic processes. In ME, positive immunoreactive axon made synaptic contact with negative axon. The contacts were often symmetrical. These data suggest that there were three types of SRIF neurons with different functions. The third type showing the high synthetic function may play an important regulative role in Pv. The study also provide morphological evidence for ultrashort feedback modulation and synchronous activity of SRIF neurons in Pv, PVN and for intronuclear modulation of SRIF neurons in VMN, ARN and SCN.